A) The initial equation is:
[tex]3x-12y=27[/tex]now to solve for x, we have to add 12y in bout sides and divide by 3 so:
[tex]\begin{gathered} 3x=27+12y \\ x=\frac{27+12y}{3} \\ x=9+4y \end{gathered}[/tex]B) the inital equation is:
[tex]6x-7y=-2[/tex]To solve it we have to add 7y and divide by 6 so:
[tex]\begin{gathered} 6x=-2+7y \\ x=\frac{-2+7y}{6} \end{gathered}[/tex]C) the initial equation is:
[tex]4x-k=17[/tex]To solve it we have to add k and divide by 4 so:
[tex]\begin{gathered} 4x=17+k \\ x=\frac{17+k}{4} \end{gathered}[/tex]D) the initial equation is:
[tex]kx+c=9[/tex]To solve it we have to rest c and divide by k so:
[tex]\begin{gathered} kx=9-c \\ x=\frac{9-c}{k} \end{gathered}[/tex]